1. Field of the Invention
The present invention is generally related to a point symmetry shaping method used for a curved figure, and also a point symmetry shaping apparatus used for the curved figure. More specifically, the present invention is directed to such point symmetry shaping method/apparatus used for a curved figure, capable of extracting a symmetry center point used to point-symmetry shape an input curved figure, and also capable of shaping this input curved figure in a point symmetry manner with respect to this extracted symmetry center point.
2. Description of the Related Art
Point-symmetry-figure shaping apparatuses for shaping input curved figures in a point symmetry manner are known in this field, for example, as described in Japanese Patent Laid-open Application No. Sho62-111369 published in 1987. These conventional point-symmetry-figure shaping apparatuses are normally employed so as to automatically design drawings and the like and to recognize figure symbols illustrated in these read design drawings.
FIG. 15 is a schematic block diagram for indicating one example of this sort of conventional point symmetry shaping apparatus used for a curved figure. As indicated in this drawing, this conventional point symmetry figure shaping apparatus is arranged by a symmetry shape recognition processing unit 101, a symbol table 102, and a symmetry converting unit 103. The symmetry shape recognition processing unit 101 is constituted by a symmetry shape judging unit 111 and a comparing unit 112.
Referring to the above-explained block diagram of FIG. 15 and a flow chart of FIG. 16, operations of this conventional point symmetry shaping apparatus will be described as follows. In this conventional point symmetry shaping apparatus, an image which is entered to be recognized is read as binary image data. After a symbol element is extracted from this read binary image data, the resultant image data is entered into the recognition processing unit 101. The recognition processing unit 101 performs the symbol recognition process of this entered curved figure to output a recognition result "a" as the recognition result (steps V10 and V11 of FIG. 16).
The symmetry shape judging unit 11 judges as to whether or not the recognition result "a" is equal to a symbol of a symmetry shape (step V12). This judgment is carried out by referring to the symbol table 102. This symbol table 102 defines a classification of a symmetry symbol and an asymmetry symbol. At this time, if the above-explained symbol is not equal to the symmetry shape, then the recognition processing unit 101 outputs this recognition result "a" as the recognition result (step V19).
To the contrary, in the case that the symmetry shape judging unit 111 judges that the above-described symbol is equal to the symmetry shape, the input image is symmetrically converted by the symmetry converting unit 103 (step V13). Next, the symmetry-converted image is again recognized by the recognition processing unit 101. As a result of this recognition, another recognition result "b" is obtained (steps V14 and V15). Subsequently, the comparing circuit 112 performs the comparison operation as to whether or not the recognition result "a" is made coincident with the recognition result "b" (step V16). When the recognition result "a" is made coincident with the recognition result "b", the recognition processing unit 101 outputs this recognition result "b" as the result thereof. Conversely, when the recognition result "a" is not made coincident with the recognition result "b", this recognition processing unit 101 rejects the input image data as "judgment impossible" (step V18).
As previously described, in accordance with the above-described conventional point symmetry shaping apparatus used for the curved figure, the input image data is symmetrically converted, and thereafter the symmetrically converted image data is again recognized under such an assumption that when the recognition result of the image under recognition is equal to the symmetry shape symbol, this image under recognition itself owns the symmetry. Only when it is judged that the recognition result "a" is made coincident with the recognition result "b", this input image is recognized as the recognition result "b".
However, this conventional point symmetry shaping apparatus used for the curved figure owns the following problem. That is, since all of the figures which are wanted to be judged as the symmetry figures must be defined in the symbol table 102, in such a case that one symmetry figure not defined in this symbol table 102 is entered into this conventional point symmetry shaping apparatus, this newly entered symmetry figure cannot be judged as a "symmetry figure".